Laser power setting method and optical recording device

ABSTRACT

At ST 1,  the process identifies whether apparatus identification information of an optical recording apparatus is recorded in an optical recording medium and, if it is not recorded, if the recorded information does not agree with apparatus identification information of the optical recording apparatus, or if they agree but information validation conditions are not met, it performs processing of ST 2  and ST 3  to perform power calibration processing of laser light and calculate power set values. At ST 4,  the process records power calibration information and the apparatus identification information in the recording medium. If the information agrees and the information validation conditions are met, the process performs processings of ST 9  and ST 10  to calculate power set values using already created information. At ST 5,  the process sets laser light power based on the power set values. If a recording medium, which has once been used, is used, recording of a signal can start immediately in a condition where the laser light power is optimized.

TECHNICAL FIELD

The present invention relates to a laser power setting method and anoptical recording apparatus.

BACKGROUND ART

In an optical recording apparatus using an optical recording medium, adisc is irradiated with laser light sent from an optical pickup so thata signal may be recorded on the disc. Further, power of the laser lightis switched to read the signal recorded on the disc.

In such an optical recording apparatus, power of laser light iscontrolled to irradiate a disc with the laser light so that pitscorresponding to a signal to be recorded may be formed in the disc. Inthis case, if the power of the laser light is not appropriate, a shapeof the pits may be too large or too small, thus making it impossible toread the recorded signal correctly. Therefore, performed is so-calledpower calibration processing such that trial writing is performedutilizing, for example, a region on an innermost side or an outermostside of the disc and based on a result of this trial writing, the laserlight power may be set optimally.

Note here that in the power calibration processing, a signal is recordedin a region on the innermost or outermost side with power of laser lightaltering and, based on a reproduced signal obtained by reproducing therecorded signal, optimal laser light power is determined. Therefore,this requires time for recording a signal, time for reproducing therecorded signal to determine laser light power, a movement time formoving an optical pickup between the innermost side and the outermostside, etc., and thus, it takes long time required for processing.

Therefore, if power calibration processing is performed to set laserlight power to an optimal state when a removable disc is mounted to anoptical recording apparatus, an operation to record a signal cannot bestarted until the power calibration processing is completed. If a buffermemory is provided to record a signal supplied during power calibrationprocessing when it takes a long time to perform the power calibrationprocessing, a large capacity buffer memory must be provided, thusincreasing costs of a relevant optical recording apparatus.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a laser powersetting method and an optical recording apparatus in which recording ofa signal may start immediately without requiring a buffer memory and asignal may be recorded in a condition where laser light power isoptimized.

A laser power setting method related to the present invention comprisesa first identification step for identifying whether apparatusidentification information assigned to an optical recording apparatus isrecorded in an optical recording medium, the apparatus identificationinformation being unique to the optical recording apparatus, a secondidentification step for identifying whether the apparatus identificationinformation recorded in the optical recording medium, if it isidentified that the apparatus identification information has beenrecorded in the first identification step, agrees with the apparatusidentification information unique to the apparatus, a first processingstep for performing first processing when a first identification resultis obtained which includes a result of a case where it is identified inthe first identification step that the apparatus identificationinformation is not recorded and a result of a case where it isidentified in the second identification step that the recorded apparatusidentification information does not agree with the apparatusidentification information assigned to the optical recording apparatus,and a second processing step for performing second processing under atleast one condition that a second identification result is obtained, thesecond identification result including a result of a case where it isidentified in the first identification step that the apparatusidentification information is recorded and a result of a case where itis identified in the second identification step that the recordedapparatus identification information agrees with the apparatusidentification information assigned to the optical recording apparatus,wherein the first processing step includes a creation step for creatingpower calibration information by performing power calibration processingand a setting step for setting laser light power based on the powercalibration information created in the creation step, and wherein thesecond processing step includes a step for setting laser light powerbased on the power calibration information recorded in the opticalrecording medium.

A second laser power setting method comprises a first identificationstep for identifying whether recording medium identification informationassigned to an optical recording medium is stored in storage means of anoptical recording apparatus, the recording medium identificationinformation being unique to the optical recording medium, a secondidentification step for identifying whether the recording mediumidentification information recorded in the optical recording medium, ifit is identified that the recording medium identification informationhas been stored in the first identification step, agrees with recordingmedium identification information stored in the storage means, a firstprocessing step for performing first processing when a firstidentification result is obtained which includes a result of a casewhere it is identified in the first identification step that therecording medium identification information is not stored and a casewhere it is identified in the second identification step that therecorded recording medium identification information does not agree withthe recording medium identification information assigned to the opticalrecording medium, and a second processing step for performing secondprocessing under at least one condition that a second identificationresult is obtained, the second identification result including a resultof a case where it is identified in the first identification step thatthe recording medium identification information is stored and a resultof a case where it is identified in the second identification step thatthe stored recording medium identification information agrees with therecording medium identification information assigned to the recordingmedium, wherein the first processing step includes a creation step forcreating power calibration information by performing power calibrationprocessing and a setting step for setting laser light power based on thepower calibration information created in the creation step, and whereinthe second processing step includes a step for setting laser light powerbased on the power calibration information stored in the storage means.

An optical recording apparatus related to the present inventioncomprises an optical pickup for irradiating an optical recording mediumwith laser light to record or reproduce a signal, drive means fordriving the optical pickup to emit the laser light, storage means forstoring apparatus identification information unique to the apparatus,and control means for controlling operations of the optical pickup andthe drive means, wherein the control means allows for identifyingwhether the apparatus identification information is recorded in theoptical recording medium, when it is determined that the apparatusidentification information is recorded, identifying whether theapparatus identification information recorded in the optical recordingmedium agrees with apparatus identification information unique to theapparatus, performing first processing when a first identificationresult is obtained which includes a result of a case where it isidentified that the apparatus identification information is not storedand a result of a case where it is identified that the recordedapparatus identification information does not agree with the apparatusidentification information assigned to the optical recording apparatus,and performing second processing under at least one condition that asecond identification result is obtained, the second identificationresult including a result of a case where it is identified that theapparatus identification information is recorded and a result of a casewhere it is identified that the recorded apparatus identificationinformation agrees with the apparatus identification informationassigned to the optical recording apparatus, wherein in the firstprocessing, power calibration information is created performing powercalibration processing and, based on the created power calibrationinformation, laser light power is set, and wherein in the secondprocessing, laser light power is set based on power calibrationinformation recorded in the optical recording medium.

A second optical recording apparatus comprises an optical pickup forirradiating an optical recording medium with laser light to record orreproduce a signal, drive means for driving the optical pickup to emitthe laser light, storage means for storing recording mediumidentification information unique to the optical recording medium, andcontrol means for controlling operations of the optical pickup and thedrive means, wherein the control means allows for identifying whetherthe recording medium identification information is stored in the storagemeans, when it is determined that the recording medium identificationinformation is recorded, identifying whether the recording mediumidentification information recorded in the optical recording mediumagrees with the recording medium identification information stored inthe storage means, performing first processing when a firstidentification result is obtained which includes a result of a casewhere it is identified that the recording medium identificationinformation is not recorded and a result of a case where it isidentified that the stored recording medium identification informationdoes not agree with the recording medium identification informationassigned to the optical recording medium, and performing secondprocessing under at least one condition that a second identificationresult is obtained, the second identification result including a resultof a case where it is identified that the recording mediumidentification information is stored and the stored recording mediumidentification information agrees with the recording medium informationassigned to the optical recording medium, and wherein in the firstprocessing, power calibration information is created performing powercalibration processing and, based on the created power calibrationinformation, laser light power is set, and wherein in the secondprocessing, laser light power is set based on power calibrationinformation stored in the storage means.

According to the present invention, where information is recorded in anoptical recording medium by an optical recording apparatus, recordingmedium identification information of the optical recording medium andrecording medium identification information stored in the opticalrecording apparatus are compared to each other or apparatusidentification information recorded in the optical recording medium andapparatus identification information assigned to the optical recordingapparatus are compared to each other, so that if a comparison result ofthese pieces of identification information indicates that the opticalrecording medium has never been used, power calibration processing isperformed to create power calibration information and, based on thispower calibration information, laser light power is set.

Further, where it is identified from the comparison result that theoptical recording medium has once been used or where the opticalrecording medium is identified to have once been used and alreadycreated power calibration information is identified to meet informationvalidation conditions, based on this created power calibrationinformation, laser light power is set. If it is identified that theinformation validation conditions are not met, on the other hand, thelaser light power is set on the basis of power calibration informationcreated by the power calibration processing. Furthermore, when the powercalibration processing is performed, created power calibrationinformation and apparatus identification information are recorded in theoptical recording medium or the created power calibration informationand recording medium identification information are stored in theoptical recording apparatus.

According to the present invention, recording medium identificationinformation of the optical recording medium and recording mediumidentification information stored in the optical recording apparatus arecompared to each other or apparatus identification information recordedin the optical recording medium and apparatus identification informationassigned to the optical recording apparatus are compared to each other,so that based on a comparison result of these pieces of identificationinformation, performing of power calibration processing is controlled.Therefore, if the optical recording medium has once been used, alreadycreated power calibration information can be utilized to start arecording operation immediately in an optimal state.

If the optical recording medium has not been used, on the other hand,the power calibration processing is performed, so that the created powercalibration information and the apparatus identification information arerecorded in the optical recording medium or the created powercalibration information and the recording medium identificationinformation are stored in the optical recording apparatus. Therefore,when the same optical recording medium is used again, it is possible toidentify whether the optical recording medium has once been usedcorrectly.

Furthermore, information validation conditions are set to powercalibration information, so that if the information validationconditions are not met, the power calibration processing is performed.Therefore, before such a case occurs that a recording operation cannotbe performed in an optimal state using already created power calibrationinformation, the power calibration processing is performed to update thepower calibration information, thereby always performing the recordingoperation in the optimal state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for showing a configuration of a disc;

FIG. 2 is a block diagram for showing a configuration of an opticalrecording apparatus;

FIG. 3 is a flowchart for showing a first embodiment; and

FIG. 4 is a flowchart for showing a second embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

The following will describe embodiments of the present invention withreference to drawings. FIG. 1 shows an optical recording medium, forexample, an optical disc (hereinafter referred to as “disc”), in which asignal is recorded using laser light and FIG. 2 shows a configuration ofan optical recording apparatus for recording a signal using the discshown in FIG. 1.

In FIG. 1, on an inner periphery side of a disc 10, a trial-writingregion A is provided. This trial-writing region A is used to record atest signal and reproduce this recorded test signal, thereby determiningoptimal laser light power. On an outer periphery side of thetrial-writing region B, a buffer region B is provided. The buffer regionB is provided to record information etc. that indicates a recordingposition in a case where a signal is recorded.

Furthermore, on an outer periphery side of the buffer region B, thereare provided a lead-in region C for recording table of contents (TOC)data, a program region D for recording a signal, and a lead-out region Efor indicating an outermost periphery of the recording region toward theouter periphery in this order. Further, an outer periphery side of thelead-out region E provides an outer periphery region F.

Note here that a layout of these regions on the disc 10 is justillustrative and not restrictive. For example, the trial-writing regionA, the buffer region B, etc. may be provided from the outer peripheryside in this order. Further, of course these regions may be replaced inorder.

Next, an optical recording apparatus 20 is described. In FIG. 2, theremovable disc 10 mounted on a turntable 21 is driven rotationally by aspindle motor 22. Note here that the spindle motor 22 is driven so thata rotational speed of the disc 10 may become a desired speed by aspindle drive signal SSD obtained from a motor drive portion 35described later.

An optical pickup 25 comprises a laser light emission device forirradiating the disc 10 with laser light, a photodetector for receivinglaser light reflected by a signal face of the disc 10 to generate anelectrical signal that corresponds to the reflected light, an objectivelens for reflecting laser light to a desired position on the signal faceof the disc 10 correctly, an actuator for driving an objective lens,etc. This optical pickup 25 irradiates the disc 10 with laser lighthaving a controlled light quantity. The laser light reflected by thedisc 10 is applied to a photo-detection/processing circuit (not shown)of the optical pickup 25. The photo-detection/processing circuitperforms photoelectric transfer, current/voltage conversion, etc. togenerate a photo-detection signal Sde based on the reflected light andsupply it to an RF signal processing portion 26. Further, thephoto-detection/processing circuit monitors laser light power togenerate a power monitor signal Spm and supply it to a laser driveportion 34 described later.

The RF signal processing portion 26 generates a read-out signal Sr basedon the photo-detection signal Sde and performs waveform shaping,binarization, etc. of this read-out signal Sr to generate a clock signalCLK and a reproduced signal RDa and supply them to a reproduced-signalprocessing portion 30. Further, it generates a tracking error signal STEand a focus error signal SFE based on the photo-detection signal Sde andsupply them to a servo control portion 27. Further, it supplies theread-out signal Sr to a decision signal generation portion 28.

Based on the supplied focus error signal SFE, the servo control portion27 generates a focus drive signal SFD to drive an objective lens (notshown) of the optical pickup 25 so that a focal position of the laserlight may be set on the signal face of the disc 10 and supplies it tothe actuator of the optical pickup 25 (not shown). Further, based on thesupplied tracking error signal STE, the servo control portion 27generates a tracking drive signal STD for driving the objective lens ofthe optical pickup 25 so that an irradiation position by the laser lightmay be set on a midpoint of a desired track and supplies it to theactuator. Furthermore, since a tracking servo range of the opticalpickup 25 is restricted, the servo control portion 27 generates a threaddrive signal to move the optical pickup 25 in a radial direction of thedisc 10 so that ID a signal recording or read-out position may providethe tracking servo range and supplies it to a thread drive circuit (notshown). Further, based on a servo control signal CS obtained from acontrol portion 40, the servo control portion 27 controls servooperations. For example, the servo control portion 27, when mounted withthe disc 10, performs a focus research operation based on the servocontrol signal CS obtained from the control portion 40 to detect aposition of the objective lens where the focal point of the laser lightmay be set on the signal face of the disc 10 and starts a focus servooperation. Further, to move a signal read-out position, the servocontrol portion 27 temporarily stops the tracking servo operation basedon the servo control signal CS obtained from the control portion 40 andjumps tracks to move the signal read-out position rapidly in a radialdirection.

The reproduced-signal processing portion 30 uses the clock signal CLK toperform such processing as demodulation, de-interleaving,error-correcting, etc. on the reproduced signal RDa and supplies apost-processing signal RDb to an output processing portion 31. Further,a signal RDb obtained by reading a signal present in a predeterminedregion of the disc 10 or a signal indicating an address position issupplied to the control portion 40.

The output processing portion 31 performs decode-processing on thesupplied signal RDb if it is a signal obtained by encoding images orvoice. Furthermore, the output processing portion 31 outputs a signalobtained by decode-processing as an output signal RDc given in apredetermined output format. Further, if the signal RDb is not anencoded signal, the output processing portion 31 outputs a signalsupplied from the reproduced-signal processing portion 30 as the outputsignal RDc given, in the predetermined format. Furthermore, if thesupplied signal is a data signal of computer software etc., the outputprocessing portion 31 outputs a signal supplied from thereproduced-signal processing portion 30 as it is.

An input processing portion 32, when supplied with an input signal WDaof images or voice, encodes this input signal WDa to reduce its signalquantity and supplies an encoded signal as a signal WDb to arecording-signal processing portion 33. Further, not to reduce thesignal quantity, the input processing portion 32 supplies the inputsignal WDa as the signal WDb to the recording-signal processing portion33. Further, if the input signal WDa is not given in the predeterminedformat, the input processing portion 32 converts a format of the inputsignal WDa and supplies a converted signal as the signal WDb to therecording-signal processing portion 33. Furthermore, if data of computersoftware etc. is supplied as the input signal WDa, the input processingportion 32 supplies this data signal as the input signal WDa to therecording-signal processing portion 33.

The recording-signal processing portion 33 performs such processing asmodulation, interleaving, error-correcting code calculation andaddition, etc. on the signal WDb supplied from the input processingportion 32, to generate a recording signal WS. Further, when suppliedwith a test signal WDc for power calibration from the control portion40, the recording-signal processing portion 33 generates the recordingsignal WS based on this test signal WDc and supplies it to a laser driveportion 34.

The decision signal generation portion 28 generates, based on thesupplied read-out signal Sr, a decision signal LM, which makes itpossible to determine whether a signal has been written at appropriatelaser power. For example, if a predetermined pattern signal is recordedby varying laser light power and this recorded pattern signal isreproduced, a maximum level and a minimum level of a signal obtained inreproduction fluctuate in accordance with the laser light power.Therefore, a signal level of the read-out signal Sr is detected and asignal that indicates this signal level is supplied as the decisionsignal LM to the control portion 40.

The laser drive portion 34 generates a laser drive signal SLD andsupplies it to the laser light emission device of the optical pickup 25to thereby control the laser light power with which the disc 10 isirradiated. In this case, the laser drive portion 34 generates the laserdrive signal SLD so that the laser light power based on a laser powerset value CL supplied from, for example, the control portion 40 may beswitched in accordance with the recorded signal WS supplied from therecorded-signal processing portion 33.

A temperature sensor 36 measures a temperature of the disc 10 or a spacenear the disc 10 and supplies the control portion 40 with a sensorsignal TSa that indicates a measurement result. The temperature sensor37 measures a temperature of the laser light emission device andsupplies the control portion 40 with a sensor signal TSb that indicatesa measurement result.

The motor drive portion 35 generates the spindle drive signal SSD basedon a motor control signal MC supplied from the control portion 40 andsupplies it to the spindle motor 22.

To the control portion 40, a user interface 41 is connected. The userinterface 41 generates a control signal PS in accordance with useroperations and supplies it to the control portion 40. Alternatively, theuser interface receives a remote-control signal in accordance with useroperations and supplies it as the control signal PS to the controlportion 40. Further, the user interface 41 receives a signal, whichcontrols operations of the optical recording apparatus from an externaldevice, and supplies it as the control signal PS to the control portion40.

The control portion 40 controls operations of the various portions basedon the control signal PS supplied from the user interface 41, to set theoperations of the optical recording apparatus in an operation mode thatis in accordance with user operations, etc. Further, the control portion40 generates a laser power set value CL for setting laser light power inaccordance with the operation mode and supplies it to the laser driveportion 34.

Further, in power calibration processing, the control portion 40generates the laser power set value CL so as to change laser light powercontinuously or stepwise and supplies it to the laser drive portion 34and supplies the test signal WDc to the recorded-signal processingportion 33 to perform trial writing in the trial writing region A or theouter periphery region F. Furthermore, the control portion 40 determinesa laser power set value CLA at which the laser light power is optimizedon the innermost periphery side based on the decision signal LM suppliedfrom the decision signal generation portion 28 when the test signal WDcin the trial writing region A is reproduced and determines a laser powerset value CLF at which the laser light power is optimized on theoutermost periphery side based on the decision signal IM supplied fromthe decision signal generation portion 28 when the test signal WDc inthe outer periphery region F is reproduced.

Furthermore, the control portion 40 provides identification informationthat allows for identifying whether a disc of interest has once beenused, and power calibration information generated by using determinedlaser power set value and various pieces of information obtained whenpower calibration processing is performed, to the disc or the opticalrecording apparatus. For example, apparatus identification informationassigned uniquely to, for example, the optical recording apparatus andpower calibration information are recorded in a predetermined region ofthe disc 10. Alternatively, recording medium identification informationassigned uniquely to the disc and power calibration information arestored in a memory 42 in such a manner that they may correspond to eachother.

This apparatus identification information is comprised of an ID foridentifying, for example, a developer and manufacturer of an apparatus,a model name of the apparatus, a serial number of the apparatus, etc.The recording medium identification information is comprised of an IDfor identifying a developer and manufacturer of, for example, a disc, aproduct name of the disc, a serial number of the disc, etc. Further, ina case where fluctuations are small in a production lot of a disc, aproduction lot number etc. of the disc may be used. The powercalibration information is comprised of a laser power set value,information for determining a change-over-time in properties of thelaser light emission device (e.g., elapsed operating time of the laserlight emission device, date, etc. when power calibration processing isperformed), information about an operating environment of the laserlight emission device (e.g., temperature of the laser light emissiondevice), information indicating intrinsic properties of the laser lightemission device, etc. Furthermore, information about properties of thedisc etc. may be used.

Further, the apparatus identification information is to be storedbeforehand in a nonvolatile memory equipped to, for example, the controlportion 40 so that general users cannot rewrite the information.Furthermore, if the optical pickup is replaced to accommodate services,by updating the apparatus identification information stored in thenonvolatile memory, power calibration information can always be held ina proper state.

The recording medium identification information can be recorded at anyposition as far as the optical recording apparatus can read it there,such as an innermost periphery side or outermost periphery side region,a lead-in region, a program region, etc. of a disc. Further, byrecording the recording medium identification information near aposition which is irradiated with laser light in a place of the opticalpickup which is set first when the optical recording apparatus startsits operations, it is possible to read this information without movingthis optical pickup 25 radially, thereby immediately identifying whethera disc of interest has once been used.

Furthermore, such a disc 10 as to have a memory embedded in it may beused as the optical recording medium or the disc 10 may be contained ina cartridge provided with a memory, to constitute the optical recordingmedium. Further, by providing a memory as well as a wirelesstransmission/reception circuit, information can be recorded andreproduced in a non-contact operation, thereby identifying whether thedisc of the interest has once been used only by mounting the opticalrecording medium to the optical recording apparatus without rotating thedisc 10.

The control portion 40 determines whether power calibration processingis necessary based on identification information or power calibrationinformation attached to the memory 42 or the disc 10 and, if such is thecase, performs the power calibration processing. Further, in recordingof a signal, it sets laser light power based on power calibrationinformation attached to the memory 42 or the disc 10 or laser power setvalues CIA and CLF of power calibration information generated byperforming the power calibration processing. Note here that the controlportion 40 generates the servo control signal CS to control operationsof the servo control portion 27.

Next, operations of the optical recording apparatus will be described.If a signal is recorded on the disc 10, the optical recording apparatus20 identifies whether the disc 10 has once been used and, when it hasnever been used, the calibration processing is performed utilizing thedisc 10, thereby determining a laser power set value, which optimizeslaser light power. Then, this determined laser power set value is usedto perform recording. If it has once been used, an already set laserpower set value is used to start recording, omitting the powercalibration processing.

Further, emission properties of the laser light emission device varywith, for example, an operating temperature, an elapsed operating time,etc. Therefore, information validation conditions are set so thatvariations of laser light power owing to the operating temperature, theelapsed operating time, etc. may fall in a desired range, so that ifpower calibration information fails to meet any information validationconditions, a laser power set value contained in the power calibrationinformation is invalidated to perform the power calibration processingagain, thereby updating the laser power set value.

FIG. 3 is a flowchart for showing a first embodiment of the operationsof the optical recording apparatus. According to this first embodiment,identification information used to identify whether the disc 10 has oncebeen used and power calibration information are recorded on the disc 10,so that the optical recording apparatus utilizes the informationrecorded on the disc 10 to thereby set laser light power.

The control portion 40 of the optical recording apparatus identifieswhether apparatus identification information is recorded in apredetermined region of the disc 10 at step ST1. In this case, to usethe disc 10 for the first time, the process goes to step ST2 because noapparatus identification information is recorded.

At step ST2, power calibration processing is performed to set a laserpower set value that optimizes laser light power and stores this laserpower set value in the memory 42.

In this power calibration processing, the control portion 40 controlsoperations of the servo control portion 27, the recording signalprocessing portion 33, the laser drive portion 34, the motor driveportion 35, etc., to record the test signal WDc in the trial writingregion A of the disc 10 when it is being driven rotationally at adesired speed. Further, when the test signal WDc is recorded, the laserpower set value is changed continuously or stepwise to vary the laserlight power.

Next, the control portion 40 performs control processing for reproducingthe recorded test signal WDc and sets a laser power set value at a timewhen the best signal has been obtained based on the decision signal LMsupplied from the decision signal generation portion 28 as an optimallaser power set value CIA on the inner periphery side. This optimallaser power set value CLA on the inner periphery side is stored in thememory 42.

When the operations for setting the laser power set value on thetargeted inner periphery side are finished, the optical pickup 25 ismoved toward the outer periphery side, so that as in the case of theinner periphery side, it records and reproduces the test signal WDc andsets a laser power set value at a time when the best signal has beenobtained based on the decision signal LM as an optimal laser power setvalue CLF on the outer periphery side. This optimal laser power setvalue CLF on the outer periphery side is stored in the memory 42.

At step ST3, the inner periphery side laser power set value CLA and theouter periphery side laser power set value CLF, which are stored in thememory 42, are used to calculate a laser power set value CL at eachposition in a radial direction of the disc 10. If the laser power setvalue CL at each position is calculated on the basis of a calculationequation set in accordance with recording properties of the disc 10, anoptimal laser power set value CL can be obtained. The recordingproperties of the disc 10 can be determined on the basis of a change inthe test signal, which has been recorded in the trial writing region Abeforehand. Alternatively, the recording properties may be determined byreading data, which has been set for each disc manufacturer and recordedon the disc.

At step ST4, it controls operations of the servo control portion 27, therecording signal processing portion 33, the laser drive portion 34, themotor drive portion 35, etc. and records apparatus identificationinformation and power calibration information on the disc 10. By thusrecording the apparatus identification information on the disc 10, it ispossible to correctly identify whether the disc has once been used.

The power calibration information is created using various pieces ofinformation obtained when the power calibration processing is performedas described above, the power calibration information comprising, forexample, dates and times when the power calibration processing has beenperformed, an elapsed operating time of the laser light emission deviceat a time when the power calibration processing has been performed, atemperature TMa of the disc 10 or a neighborhood of the disc 10 and atemperature TMb of the optical pickup 25, an inner periphery side laserpower set value CLA and an outer periphery side laser power set valueCLF, information about the laser light emission device, etc.

The apparatus identification information and the power calibrationinformation are recorded in a predetermined region of the disc 10, forexample, the trial writing region A or the outer periphery region F.Note here that the recording region is not limited to these but apredetermined region may be previously allocated in, for example, theprogram region to record it in the region. By thus determining therecording region beforehand, the apparatus identification informationand the power calibration information can be read immediately. Further,if positions where the apparatus identification information and thepower calibration information are recorded can be managed, of coursethey can be recorded at any positions in a blank area on the disc.

At step ST5, the laser power set value CL at each position in a radialdirection of the disc calculated from the laser power set value CIA ofthe inner periphery side and the laser power set value CLF of the outerperiphery side are supplied to the laser drive portion 34 in accordancewith the signal recording position, thereby recording the signal in theprogram region D using laser light power based on this laser power setvalue CL. In this case, the signal recording position can be determinedeasily by reading address information which is given in wobbles, pits,etc. on the disc 10. Further, in accordance with the radial position ofthe optical pickup 25, the corresponding laser power set value CL may besupplied to the laser drive portion 34.

Further, if the temperature of the optical pickup 25 changes duringrecording of the signal, the power or wavelength of the laser lightchanges, thereby changing the recording properties of the disc 10.Further, the recording properties change even with a change intemperature of the disc 10. Therefore, the control portion 40 correctsthe laser power set value CL based on the sensor signals TSa and TSb. Bythus correcting the laser power set value CL, it is possible to continuesignal recording at optimal laser light power.

Furthermore, by recording information data etc. that indicates recordingpositions of the signal etc. in the buffer region B or the lead-inregion C when the recording operation has finished, this recordedinformation can be utilized to easily set a position at which the nextrecording operation starts.

If the disc 10 has once been used, it means that the apparatusidentification information and the power calibration information havebeen recorded on the disc 10 at step ST4. Therefore, the process goesfrom step ST1 to step ST6 to read the apparatus identificationinformation and the power calibration information recorded on the disc10 and goes to step ST7.

At step ST7, it identifies whether the read apparatus identificationinformation agrees with apparatus identification information of anoptical recording apparatus that uses this disc 10. In this case, if thedisc has once been used, these pieces of apparatus identificationinformation agree with each other, so that the process goes to step ST8.Further, if the disc 10 has once been used in any other opticalrecording apparatus, apparatus identification information assigned tothis optical recording apparatus is recorded. Therefore, the readapparatus identification information and the apparatus identificationinformation of the optical recording apparatus do not agree, so that theprocess goes from step ST7 to step ST2 to perform the power calibrationprocessing again, thereby determining a laser power set value inaccordance with the optical recording apparatus that uses the disc 10.

At step ST8, it determines whether the power calibration informationmeets any information validation conditions. If the informationvalidation conditions are met, the process goes to step ST9 and,otherwise, returns to step ST2.

The information validation conditions have been set so that laser lightpower variations may fall in a desired range, as described above. Notehere that the information validation conditions are set so that laserlight power variations due to deterioration of the laser light elementmay fall in a desired range, including settings such as the number ofdays which have elapsed since the power calibration processing wasperformed and a difference in elapsed operating time between an elapsedoperating time at a time when the power calibration processing wasperformed and a current elapsed operating time of the laser lightemission device. Further, to contain laser light power variations due totemperature variations within a desired range, the settings include adifference in temperature between a temperature at a time when the powercalibration processing was performed and a current temperature.Furthermore, the settings include conditions taking into account adifference in properties of the laser light emission device, such as athreshold value Hth of the operating temperature based on the intrinsicproperties of the laser light emission device (e.g., Hth=Hre+kM is used,where Hre is a reference value, k is intrinsic properties of the laserlight emission device, and M is a constant). Note here that the powercalibration information contains such information as a date when thepower calibration processing was performed, an elapsed operating time ofthe laser light emission device when the power calibration processinghas been performed, and a temperature at which the power calibrationprocessing was performed.

In this case, if the number of elapsed days or the difference in elapsedoperating time exceeds a predetermined value, the temperature differencegoes out of a predetermined range, or an operating temperature exceedsits threshold value, the information validation conditions may not bemet, that is, the laser light power variations may go out of a desiredrange, so that the process goes to step ST2 to control the variousportions so that the signal may be recorded after the laser power valueis set again. If neither the number of elapsed days nor the differencein elapsed operating time exceeds the predetermined value and thetemperature difference is within the predetermined range and theoperating temperature does not exceed its threshold value, on the otherhand, the information validation conditions are met, that is, the laserlight power variations are within a desired range, so that the processgoes to step ST9.

In such a manner, by establishing processing of step ST8, thecalibration processing is performed automatically if the informationvalidation conditions are not met, so that the signal can be recorded ina condition where the laser light power is optimized. For example, iflaser light power deteriorates due to a variation in emission propertiesof the laser light emission device even when the laser light power isset on the basis of the laser power set values CLA and CLF, thecalibration processing is performed automatically. It is thus possibleto prevent the signal from being recorded on the disc 10 in a conditionwhere laser light power is small, thereby recording the signal atoptimal power.

Further, in a case where such a disc is used as to have a largeallowance in laser light power variations at the time of signalrecording or a laser light emission device that has small variations inlaser light power is used, the signal can be recorded well withoutperforming the power calibration processing as time passes by or as thetemperature varies, so that processing of step ST8 may be omitted insuch a case.

At step ST9, the laser power set value CLA of inner periphery side andthe laser power set value CLF of outer periphery side, which have beenrecorded on the disc 10 at the above-mentioned step ST4, are read outand stored in the memory 42 and the process goes to step ST10.

At step ST10, a laser power set value CL at each position in a radialdirection of the disc 10 as in the case of step ST3 is calculated fromthe laser power set value CIA of inner periphery side and the laserpower set value CLF of outer periphery side, which have been stored inthe memory 42. Then, the process goes to step ST5 to supply the laserdrive portion 34 with the laser power set value CL in accordance withthe signal recording position and record the signal.

In such a manner, if no apparatus identification information is recordedon the disc 10 or if the recorded apparatus identification informationis different from apparatus identification information of the opticalrecording apparatus, the control portion 40 identifies that the disc 10has not been used yet and performs power calibration processing and thenrecords a signal. If the recorded identification information agrees withthe apparatus identification information of the optical recordingapparatus, on the other hand, it identifies that the disc 10 has oncebeen used and records the signal utilizing the laser power set valuescontained in the power calibration information.

Therefore, by mounting the disc 10 to the optical recording apparatus 20and performing the power calibration processing beforehand, informationrecorded on this disc can be utilized when this disc is used later, toimmediately start recording, thereby greatly reducing time for waitingfor start of signal recording. Further, since the waiting time can bereduced, it is unnecessary to provide a buffer memory etc. for holding asignal supplied during the power calibration processing, therebyconstituting the optical recording apparatus inexpensively. Furthermore,if it is feared that properties of the laser light emission device mayfluctuate as the optical recording apparatus is used or laser lightpower variations may go out of a desired range because the apparatus isused in an environment etc. having a different operating temperature,the power calibration processing is performed again to optimize thelaser power set values, thereby enabling recording the signal in anoptimal condition always.

Although the above embodiment has been described to recordidentification information and power calibration information on the disc10, almost the same operations can be performed also by storing thesepieces of information in the optical recording apparatus 20. Thefollowing will describe a case where these pieces of information arestored in the optical recording apparatus 20 according to a secondembodiment, with reference to a flowchart of FIG. 4.

The control portion 40 identifies whether recording mediumidentification information is recorded in a memory 42 of an opticalrecording apparatus 20 at step ST21. In this case, if a disc 10 is usedfor the first time, no recording medium identification information isstored on this disc, so that the process goes to step ST22.

At step ST22, as in the case of the above-mentioned step ST2, the powercalibration processing is performed to create power calibrationinformation having an optimized laser power set value. This powercalibration information is configured as in the case of theabove-mentioned step ST4. At the next step ST23, the recording mediumidentification information and the power calibration information arestored in the memory 42 in such a manner that they may correspond toeach other. By thus using the recording medium identificationinformation, it is possible to correctly identify whether a disc ofinterest has once been used.

At step ST24, a laser power set value CL of each position in a radialdirection of the disc 10 is calculated from a laser power set value CLAof inner periphery side and a laser power set value CLF of outerperiphery side. At step ST25, as in the case of step ST5, the laserpower set value CL at each position in the radial direction of the disccalculated from the power set value CLA of inner periphery side and thepower set value CLF of outer periphery side is supplied to the laserdrive portion 34 in accordance with a recording position of a signal, torecord the signal in a program region D. Note here that at step ST25also, it is possible to determine the recording position, etc. of thesignal and correct the laser power set value CL as in the case of stepST5.

If the disc 10 has once been used, the recording medium identificationinformation and the power calibration information are stored, at theabove-mentioned step ST23, in the memory 42. Therefore, the process goesfrom step ST21 to step ST26.

At step ST26, the recording medium identification information recordedon the disc 10 is read out therefrom and the process goes to step ST27.

At step ST27, it identifies whether the recording medium identificationinformation stored in the memory 42 agrees with the recording mediumidentification information read from the disc. In this case, if the dischas once been used, the recording medium identification informationstored in the memory 42 agrees with it, so that the process goes to stepST28. If the disc has never been used, on the other hand, the recordingmedium identification information of the disc is not stored in thememory 42, so that the process goes to step ST22 to perform the powercalibration processing. Then, the process performs processing forstoring the recording medium identification information and the powercalibration information in the memory 42 in such a manner that they maycorrespond to each other, calculates a laser power set value CL at eachposition, records the signal by using the calculated laser power setvalue CL, etc.

At step ST28, the power calibration information, which has been storedin such a manner as to correspond to the recording medium identificationinformation determined to agree at step ST27, is read out and theprocess goes to step ST29.

At step ST29, as in the case of the above-mentioned step ST8, itdetermines whether the power calibration information meets anyinformation validation conditions. If it meets the informationvalidation conditions, the process goes to step ST30 and, otherwise,returns to step ST22. Note here that processing of step ST29 can beomitted like step ST8.

At step ST30, a laser power set value CLA of inner periphery side and alaser power set value CLF of outer periphery side are extracted from theread power calibration information and the process goes to step ST24 tocalculate a laser power set value CL at each position in the radialdirection of the disc 10 from the laser power set value CIA of innerperiphery side and the laser power set value CLF of outer peripheryside. Further, at step ST25, a signal is recorded using the laser lightpower based on this calculated laser power set value CL.

In such a manner, if no recording medium identification information isrecorded in the memory 42 of the optical recording apparatus 20 or ifthe stored recording medium identification information does not agreewith the recording medium identification information recorded on thedisc, the process identifies that the disc has never been used andperforms the power calibration processing and records the signal. If thestored recording medium identification information agrees with therecording medium identification information recorded on the disc, on theother hand, the process identifies that the disc has once been used andrecords the signal by utilizing the laser power set values CIA and CLFcontained in the power calibration information stored in the memory 42in such a manner that it may correspond to this coincident recordingmedium identification information.

Therefore, by mounting the disc 10 to the optical recording apparatus 20and performing the power calibration processing beforehand, when thedisc is used later, it is possible to immediately start recording byutilizing information stored in the memory, thereby greatly reducingtime for waiting for the start of signal recording. Further, since thewaiting time can be reduced, it is unnecessary to provide a buffermemory etc. for holding a signal supplied during the power calibrationprocessing, thereby constituting the optical recording apparatusinexpensively. Furthermore, if it is feared that properties of the laserlight emission device may fluctuate as the optical recording apparatusis used or laser light power variations may go out of a desired rangebecause the apparatus is used in an environment etc. having a differentoperating temperature, the power calibration processing is performedagain to optimize the laser power set values, thereby allowing forrecording the signal in an always optimal condition.

Although the above embodiment has been described to use an optical disc,of course, for example, the optical recording medium may be of a cardtype etc. as far as it is capable of recording by use of laser light.

Industrial Applicability

The present invention can optimize laser light power immediately byutilizing already created power calibration information and so is wellapplicable to an optical recording apparatus using a removable recordingmedium.

1. A laser power setting method comprising: a first identification stepfor identifying whether apparatus identification information assigned toan optical recording apparatus is recorded in an optical recordingmedium, said apparatus identification information being unique to theoptical recording apparatus; a second identification step foridentifying whether said apparatus identification information recordedin said optical recording medium, if it is identified that saidapparatus identification information has been recorded in said firstidentification step, agrees with said apparatus identificationinformation unique to said apparatus; a first processing step forperforming first processing when a first identification result isobtained which includes a result of a case where it is identified insaid first identification step that said apparatus identificationinformation is not recorded and a result of a case where it isidentified in said second identification step that said recordedapparatus identification information does not agree with said apparatusidentification information assigned to said optical recording apparatus;and a second processing step for performing second processing under atleast one condition that a second identification result is obtained,said second identification result including a result of a case where itis identified in said first identification step that said apparatusidentification information is recorded and a result of a case where itis identified in said second identification step that said recordedapparatus identification information agrees with said apparatusidentification information assigned to said optical recording apparatus,wherein said first processing step includes a creation step for creatingpower calibration information by performing power calibration processingand a first setting step for setting laser light power based on thepower calibration information created in said creation step; and whereinsaid second processing step includes a second setting step for settinglaser light power based on the power calibration information recorded insaid optical recording medium.
 2. The laser power setting methodaccording to claim 1, further comprising a validation conditionidentification step for identifying whether the power calibrationinformation recorded in said optical recording apparatus meetsinformation validation condition, if it is identified in said secondidentification step that said apparatus identification informationrecorded in said optical recording medium agrees with said apparatusidentification information unique to said apparatus, wherein if it isidentified in said validation condition identification step that saidpower calibration information meets said information validationcondition, said first processing step is performed and, if it isidentified that said power calibration information does not meet saidinformation validation condition, said second processing step isperformed.
 3. The laser power setting method according to claim 2,wherein said information validation condition is set so thatfluctuations of said laser light power change within a desired range. 4.The laser power setting method according to claim 1, wherein in saidsecond processing step, said second processing is performed under acondition that a second identification result is obtained, said secondidentification result including a case where it is identified in saidfirst identification step that said apparatus identification informationis recorded and a case where it is identified in said secondidentification step that said recorded apparatus identificationinformation agrees with apparatus identification information assigned tosaid optical recording apparatus.
 5. The laser power setting methodaccording to claim 1, further comprising a recording step for recordingsaid power calibration information and apparatus identificationinformation assigned to said optical recording apparatus in said opticalrecording medium.
 6. A laser power setting method comprising: a firstidentification step for identifying whether recording mediumidentification information assigned to an optical recording medium isstored in storage means of an optical recording apparatus, saidrecording medium identification information being unique to said opticalrecording medium; a second identification step for identifying whethersaid recording medium identification information recorded in saidoptical recording medium, if it is identified that said recording mediumidentification information has been stored in said first identificationstep, agrees with recording medium identification information stored insaid storage means; a first processing step for performing firstprocessing when a first identification result is obtained which includesa result of a case where it is identified in said first identificationstep that said recording medium identification information is not storedand a case where it is identified in said second identification stepthat said recorded recording medium identification information does notagree with said recording medium identification information assigned tosaid optical recording medium; and a second processing step forperforming second processing under at least one condition that a secondidentification result is obtained, said second identification resultincluding a result of a case where it is identified in said firstidentification step that said recording medium identificationinformation is stored and a result of a case where it is identified insaid second identification step that said stored recording mediumidentification information agrees with said recording mediumidentification information assigned to said recording medium, whereinsaid first processing step includes a creation step for creating powercalibration information by performing power calibration processing and afirst setting step for setting laser light power based on the powercalibration information created in said creation step; and wherein saidsecond processing step includes a second step for setting laser lightpower based on the power calibration information stored in said storagemeans.
 7. The laser power setting method according to claim 6, furthercomprising a validation condition identification step for identifyingwhether power calibration information stored in said storage means meetsinformation validation condition, if it is identified in said secondidentification step that said apparatus identification informationstored in said storage means agrees with apparatus identificationinformation unique to said apparatus, wherein if it is identified insaid validation condition identification step that said powercalibration information meets said information validation condition,said first processing step is performed and, if it is identified thatsaid power calibration information does not meet said informationvalidation conditions, said second processing step is performed.
 8. Thelaser power setting method according to claim 7, wherein saidinformation validation condition is set so that fluctuations of saidlaser light power change within a desired range.
 9. The laser powersetting method according to claim 6, wherein in said second processingstep, second processing is performed under a condition that a secondidentification result is obtained, said second identification resultincluding a case where it is identified in said first identificationstep that said apparatus identification information is stored and a casewhere it is identified in said second identification step that saidstored recording medium identification information agrees with saidrecording medium identification information assigned to said recordingmedium.
 10. The laser power setting method according to claim 6, furthercomprising a storing step for storing said power calibration informationand recording medium identification information assigned to saidrecording medium in said storage means.
 11. An optical recordingapparatus comprising: an optical pickup for irradiating an opticalrecording medium with laser light to record or reproduce a signal; drivemeans for driving said optical pickup to emit said laser light; storagemeans for storing apparatus identification information unique to saidapparatus; and control means for controlling operations of said opticalpickup and said drive means, wherein said control means allows for:identifying whether said apparatus identification information isrecorded in said optical recording medium; when it is determined thatsaid apparatus identification information is recorded, identifyingwhether said apparatus identification information recorded in saidoptical recording medium agrees with apparatus identificationinformation unique to said apparatus; performing first processing when afirst identification result is obtained which includes a result of acase where it is identified that said apparatus identificationinformation is not stored and a result of a case where it is identifiedthat said recorded apparatus identification information does not agreewith said apparatus identification information assigned to said opticalrecording apparatus; and performing second processing under at least onecondition that a second identification result is obtained, said secondidentification result including a result of a case where it isidentified that said apparatus identification information is recordedand a result of a case where it is identified that said recordedapparatus identification information agrees with said apparatusidentification information assigned to said optical recording apparatus;wherein in said first processing, power calibration information iscreated performing power calibration processing and, based on saidcreated power calibration information, laser light power is set; andwherein in said second processing, laser light power is set based onpower calibration information recorded in said optical recording medium.12. The optical recording apparatus according to claim 11, wherein saidcontrol means allows for: identifying whether power calibrationinformation recorded in said optical recording apparatus meetsinformation validation condition if it is identified that said apparatusidentification information recorded in said optical recording mediumagrees with said apparatus identification information unique to saidapparatus; and performing said first processing if it is identified thatsaid power calibration information meets said information validationcondition and performing said second processing if it is identified thatsaid power calibration information does not meet said informationvalidation condition.
 13. The optical recording apparatus according toclaim 12, wherein said information validation condition is set so thatfluctuations of said laser light power change within a desired range.14. The optical recording apparatus according to claim 11, wherein saidcontrol means allows for performing said second processing under acondition that a second identification result is obtained, said secondidentification result including a case where it is identified that saidapparatus identification information is recorded and a case where it isidentified that said recorded apparatus identification informationagrees with said apparatus identification information assigned to saidoptical recording apparatus.
 15. The optical recording apparatusaccording to claim 11, wherein said control means allows for performingprocessing for recording said power calibration information andapparatus identification information assigned to said optical recordingapparatus in said optical recording medium.
 16. An optical recordingapparatus comprising: an optical pickup for irradiating an opticalrecording medium with laser light to record or reproduce a signal; drivemeans for driving said optical pickup to emit said laser light; storagemeans for storing recording medium identification information unique tosaid optical recording medium; and control means for controllingoperations of said optical pickup and said drive means, wherein saidcontrol means allows for: identifying whether said recording mediumidentification information is stored in said storage means; when it isdetermined that said recording medium identification information isrecorded, identifying whether said recording medium identificationinformation recorded in said optical recording medium agrees with saidrecording medium identification information stored in said storagemeans; performing first processing when a first identification result isobtained which includes a result of a case where it is identified thatsaid recording medium identification information is not recorded and aresult of a case where it is identified that said stored recordingmedium identification information does not agree with said recordingmedium identification information assigned to said optical recordingmedium; and performing second processing under at least one conditionthat a second identification result is obtained, said secondidentification result including a result of a case where it isidentified that said recording medium identification information isstored and said stored recording medium identification informationagrees with said recording medium information assigned to said opticalrecording medium; and wherein in said first processing, powercalibration information is created performing power calibrationprocessing and, based on said created power calibration information,laser light power is set; and wherein in said second processing, laserlight power is set based on power calibration information stored in saidstorage means.
 17. The optical recording apparatus according to claim16, wherein said control means allows for: identifying whether powercalibration information stored in said storage means meets informationvalidation condition if it is identified that said recording mediumidentification information stored in said storage means agrees with saidrecording medium identification information unique to said opticalrecording medium; and performing said first processing if it isidentified that said power calibration information meets saidinformation validation condition and performing said second processingif it is identified that said power calibration information does notmeet said information validation condition.
 18. The optical recordingapparatus according to claim 17, wherein said information validationcondition is set so that fluctuations of said laser light power changewithin a desired range.
 19. The optical recording apparatus according toclaim 16, wherein said control means allows for performing said secondprocessing under a condition that a second identification result isobtained, said second identification result including a case where it isidentified that said recording medium identification information isstored and a case where it is identified that said stored recordingmedium identification information agrees with said recording mediumidentification information assigned to said optical recording medium.20. The optical recording apparatus according to claim 16, wherein saidcontrol means allows for performing processing for storing said powercalibration information and recording medium identification informationassigned to said optical recording medium in said storage means.